Sweeteners are known to impart a number of characteristics to food including, without limitation, odor, flavor, mouthfeel, and aftertaste. These properties, particularly flavor and aftertaste, are well known to vary over the time of tasting, such that each temporal profile is sweetener-specific (Tunaley, A., “Perceptual Characteristics of Sweeteners”, Progress in Sweeteners, T. H. Grenby, Ed. Elsevier Applied Science, 1989)).
“Tastands” are eatable compounds that reduce or eliminate undesirable tastes in other eatables, and do so at concentrations below those concentrations at which their own tastes are perceptible. Known tastands, including 2,4-dihydroxybenzoic acid, have been claimed to reduce or eliminate undesirable aftertastes, particularly bitter and/or metallic aftertastes, in eatables containing high-intensity sweeteners. U.S. Pat. No. 5,637,618. For the sake of convenience, the term “DHB” is used herein, where appropriate, to mean 2,4-dihydroxybenzoic acid and comestible salts thereof.
Tastands have been claimed to reduce or eliminate undesirable tastes by essentially blocking the undesirable taste interaction with the receptor site on the taste bud, without the tastand's imparting a taste of its own. This mechanism has been analogized to competitive inhibition with the binding site of the receptor(s) and/or competitive inhibition with the site(s) that influences the receptor. The tastand has been described as directly interacting with the receptor site for the undesirable taste, thereby preventing interaction of the undesirable taste with the target receptor site.
Sweeteners such as saccharin and 6-methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxide potassium salt (acesulfame potassium) are commonly characterized as having bitter and/or metallic aftertastes. Products prepared with 2,4-dihydroxybenzoic acid along with these sweeteners are claimed to display reduced undesirable aftertastes. In contrast, some high-intensity sweeteners, notably sucralose (1,6-dichloro-1,6-dideoxy-β-D-fructofuranosyl-4-chloro-4-deoxy-α-D-galacto-pyranoside) and aspartame (N-L-α-aspartyl-L-phenylalanine methyl ester), display clean sweet tastes very similar to that of sugar (S. G. Wiet and G. A. Miller, Food Chemistry, 58(4):305-311 (1997)). In other words, these compounds are not characterized as having bitter or metallic aftertastes.
Still, high intensity sweeteners such as sucralose and aspartame are reported to have sweetness delivery problems, i.e., delayed onset and lingering of sweetness (S. G. Wiet, et al., J. Food Sci., 58(3):599-602, 666 (1993)). These phenomena arise via mechanisms which are biochemically distinct from those responsible for generating bitter or metallic aftertastes in response to certain other sweeteners (C.-K. Lee, Advances in Carbohydrate Chemistry and Biochemistry, 45:199-351 (1987)).